1,3-Bis(1-methyl-1H-tetrazol-5-yl)propane and its coordination polymers with Cu2Cl4 and Cu3Cl6 units

Abstract

,3-Bis(1-methyl-1H-tetrazol-5-yl)propane (bmtp) was prepared by a procedure including regioselective tert-butylation of 1,3-bis(1H-tetrazol-5-yl)propane and exhaustive methylation of the obtained 1,3-bis(2-tert-butyl-1H-tetrazol-5-yl)propane, followed by removal of the tert-butyl group from the tetrazolium salt under acidic conditions. The ligand bmtp reacts with CuCl₂·2H₂O in ethanol to give the complexes [Cu₃(bmtp)₂Cl₆(H₂O)₂]_n and [Cu(bmtp)Cl₂]_n. The transformation of [Cu(bmtp)Cl₂]_n into [Cu₃(bmtp)₂Cl₆(H₂O)₂]_n is observed in ethanol. According to single crystal X-ray analysis, [Cu(bmtp)Cl₂]_n was obtained as a mixture of polymorphic forms. They are all 1D coordination polymers, in which polymeric chains include Cu₂Cl₄ units linked to each other by two bridging ligands via the tetrazole ring N⁴ atoms. [Cu₃(bmtp)₂Cl₆(H₂O)₂]_n presents a 2D coordination polymer, including Cu₃Cl₆ units bonded to four others by ligand molecules. In this complex, the tetrazole ligands show monodentate N⁴ and bridging N³,N⁴ coordination. The temperature-dependent magnetic susceptibility measurements of this complex revealed that the copper(II) ions are antiferromagnetically coupled, showing a coupling constant J of −4.0